The present invention is generally related to a valve arrangement for a controllable two-tube vibration absorber, and more particularly, to a valve arrangement for a controllable two-tube vibration absorber with a power cylinder whose interior space is subdivided into a first and a second power chambers by means of a slidable piston, and with a balancing chamber partly filled with oil. The inventive valve arrangement includes a valve body which is actuatable by an electromechanical transducer and prestressed by means of a spring. The aforementioned valve body influences a hydraulic connection through which a unidirectional flow is passed. In the traction stage, the unidirectional flow exists between said first power chamber, on one hand, and said second power chamber jointly with said balancing chamber, on the other hand. In the thrust stage the unidirectional flow exists between said first power chamber jointly with said second power chamber, on one hand, and said balancing chamber, on the other hand.
A valve arrangement generally related to the present invention is known from the older, not anticipated patent application of this applicant, No. P 41 08 026.2. The valve arrangement of the vibration absorber shown there is configured as a single-stage slide valve. The position of the valve slide depends on the hydraulic pressure differential coming about across the slide valve, the volumetric flow rate passing through the valve, and the actuating current of the electromechanical transducer.
The prior-art valve arrangement has the disadvantage that the valve body is furnished with a ring-shaped surface which is subjectable to the hydraulic pressure existing in the first power chamber and is, therefore, not pressure-balanced. Therefore, that valve can only perform a pressure-limiting function that has a negative bearing on the functioning of the vibration absorber. The drawback is particularly acute in the range of low volumetric flow rates in which a strong transmission of vibrations takes place from the wheels to the body of an automotive vehicle which is equipped with such state-of-the-art vibration absorbers.
Therefore, one object of the present invention is to provide a valve arrangement including a valve body that is actuatable by an electromechanical transducer that improves the functioning of the vibration absorber. The present invention improves the behavior of the vibration absorber and the related desired cushioning comfort, especially in the range of low volumetric flow rates.